And have an Earth name? It seems from this episode that he never has been to Earth before. Why should he know English? He comes here and instantly starts speaking English to Miko. Also, "Wheeljack"? "Jackie"? "Jack"
or "Jackie" is an Earth name. Why should he have an Earth name before he's even been to Earth?

I enjoyed this episode for the most part, but knowing English already and having an Earth name makes no sense. Seems like more lazy writing.

I'm just going to assume they're all speaking Cybertonain. The thing is with Cybertonian vocals is that they resonate in a certain way so when you hear it, your brain interprets it as your own language.
Names like Bumblebee, Bulkhead and Ratchet end up as rough translations of there original meaning.

I just assume when two Transformers are talking, with no humans around, their dialogue is translated from Cybertronian to English for ease of understanding. As for Wheeljack understanding English so quickly, he had just as much time as the movie Transformers did to learn it, and they were plummeting through the atmosphere, trying to pick up radio waves.

I'm so sick and tired of the lame excuse of "it's a kid's cartoon so just accept it". This cartoon isn't entirely aimed at kids and Orci hinted that while it's for a largely younger audience, they aren't going to dumb it down. Maybe Wheeljack learned the language via radio transmissions on his way to Earth. Fair enough. But couldn't they have explained that in the cartoon. It's not like it would take tons of long sentences. Miko could just ask Makeshift/Wheeljack, "Hey if you've never been to Earth, how come you know English? And why do you have 'Jack' as a name?" Wheeljack doesn't even have to answer the question. Prime could have answered that by saying, "Wheeljack learned your language the same way we did by listening to Earth's radio transmissions. And like the rest of us, he adopted an Earth designated name." How long would that have taken? Not long at all and it would have made the cartoon look a lot more intelligent.

As for the Autobots and Decepticons always speaking English: that's just creative license. Technically, they are probabely not always speaking English, but Cybertronian instead. But it's all automatically translated into English for the viewers to understand. Like how the Minbari in Babylon 5 were definitely speaking their own language in their ships with no humans present but it comes out automatically translated into English for the sake of the viewers. It's like the episodes where the Autobots are talking in space. One cannot produce sound waves in a vacuum. But I assume they are not really moving their lips and talking, but rather, sending radio transmissions to eachother. They only have them move their lips and appear to make sound waves for the sake of the viewer. As for them having names with Earth words in them: how do you know if they were their original names? They are probabely just Earth designations. I can understand the creative license of having the robots appear to make sounds in a vacuum or speak English all the time. But I cannot understand why a robot who has never been to Earth would have an Earth name and automatically speak English to a kid who definitely doesn't know Cybertronian. That should have been explained and it's lazy writing that it wasn't.

It may have made the cartoon look more intelligent, but omitting it does not impact the episode. Considering you already came up with quite a plausible explanation for yourself, why wouldn't that suffice? The creators just left certain things to imagination, and isn't that part of the fun of watching a show?